Bulk metal oxides, and metal oxide coatings are of interest due to their chemical and electrical properties. For example, tin oxide is a known electrical conductor that is optically transparent in the visible spectrum. Tin oxide is used in photovoltaic cells, liquid crystal displays, and light emitting diodes. Titanium dioxide is a wide band-gap semiconductor, and is also a good oxidizing agent for photo-excited molecules or functional groups. As such, titanium dioxide has been employed as a photocatalyst material, as a sensor material, and as an electrode material, e.g., in dye-based photovoltaic cells.